Speed change mechanism of a sewing machine



June 18, 1968 KIYOSHI FUJITA 3,388,681

SPEED CHANGE MECHANISM OF A SEWING MACHINE Filed Jan. 28, 1966 2 Sheets-Sheet 1 FIG. I

A l2 6 21 lo" 7 f June 18, 1968 KIYOSHI FUJITA SPEED CHANGE MECHANISM OF A SEWING MACHINE Filed Jan. 28, 1966 2 Sheets-Sheet 2 I KW {x I United States Patent 3,388,681 SPEED CHANGE MECHANISM OF A SEWING MACHINE Kiyoshi Fuiita, Kariya, Japan, assignor to Aisin Seiki Kabushiki Kaisha, Kariya, Aichi Prefecture, Japan Filed Jan. 28, 1966, Ser. No. 523,662 Claims priority, application Japan, Feb. 5, 1965,

til/6,383

3 Claims. (Cl. 112220) ABSTRACT OF THE DISCLOSURE A speed change mechanism for a motor driven sewing machine comprising a planetary gear system provided with a driving pulley having a cone clutch device, wherein a manually actuatable control device is provided for holding the internal gear of the planetary gear system against rotation, while declutching said clutch device, to keep the speed of the machine low at the start of the driving of the pulley, and also there is provided a bobbin winder assembly which is adapted when in use to cooperate with said control device to lock the planet pinion carrier drum in a non-rotatable position, while declutching said clutch so as to obtain free rotation of the driving pulley for bobbin winding.

This invention relates to a speed change mechanism of a sewing machine, particularly of a motor driven sewing machine. With the conventional motor driven sewing machine, it is unavoidable that the starting resistance is relatively high due to the starting resistance of various associated mechanisms, such as the zigzag motion producing mechanism, making it difficult to start. During the use of a motor driven sewing machine, the operation of the machine is frequently stopped unexpectedly, especially during the operation at low speed.

The object of the present invention is to remove the above mentioned drawbacks and, with the above object in view, according to the present invention there is provided a speed change mechanism which is simple in construction and may be readily handled. According to the present invention, there is further incorporated a device for maintaining the speed change mechanism in a neutral position, in which the bobbin winder assembly may be operatively connected to the freely rotating driving pulley of the main or arm shaft.

The accompanying drawings will serve to illustrate specific embodiment of the present invention, in order that its utility and functioning will be thoroughly appreciated. It will be understood, however, that this is by way of illustration only and is not to be taken as limiting the invention in any way.

In the drawings:

FIGURE 1 is a longitudinal sectional view showing the speer change mechanism for the main shaft of a sewing machine constructed according to the present invention;

FIGURE 2 is a righthand end view of the sewing machine arm shown in FIG. 1; and

FIGURE 3 shows in detail a device for operatively connecting a bobbin winder assembly with the driving pulley shown in FIG. 1.

Referring to the drawings, the reference numeral 1 designates the sewing machine arm, to which the main or Patented June 18, 1968 arm shaft 2 is journalled. A support bushing 3 is securely mounted on the main shaft 2 by means of a pin 4. A driving pulley 5 having a hand wheel is loosely mounted on said support bushing 3, and said pulley is provided with an inner cavity 6 surrounded by outer and inner flanges. The pulley 5 has a sun gear 7 formed on the inner flange, which sun gear together with the pulley is operatively connected to a source of power not shown. The outer extension of the bushing 3 forms a planetary carrier and has planetary pinion spindles 8 which are parallel to the main shaft 2. Planetary pinions 9 loosely mounted on said spindles 8 mesh with said sun gear 7. A drum shaped outer extension is provided on the bushing 3. An intermediate bushing .11 is loosely mounted on said drum 10, and this intermediate bushing 11 is provided with an internal gear 12. which meshes with said planetary pinions 9. A cone clutch ring 13 having a wedge shaped radial section is axially slidably mounted on the intermediate bushing 11, and its outer conical face 14 is in engagement with the inner conical face 15 formed on the inner wall of the outer flange of the pulley 5. A compression spring 16 is provided normally biassing the cone clutch ring 13 backwardly to keep the conical faces 14 and 15 out of frictional engagement. The backward sliding movement of the clutch ring -13 is limited by means of a flange or collar 17 formed on the end of the intermediate bushing 11. When the cone clutch ring 13 is moved forwardly against the action of the spring 16, the outer conical face 14 of the clutch ring 13 will come to a frictional engagement with the inner conical face 15 of the pulley 5, so that the pulley 5 and the intermediate bushing 11 will be operatively coupled by the intermediary of the clutch ring 13. When the forward pressure upon the clutch ring -13 is released, the latter will return to its retracted position by the action of the spring 16, in which position the conical faces 14 and 15 are out of engagement, thus releasing the operative connection of the pulley 5 and the intermediate bushing 11.

A transverse rigid shaft 18 is provided, on which an L-shaped lever 19 is pivotally mounted. This lever is provided with a spring 20 tending normally to turn the lever in the clockwise direction. A control device in the form of the free end of the short arm 21 of the lever 19 is adapted to engage selectively with a recess 23 formed in the flange 22 of the drum extending from the support bushing 3, or with a recess 24 formed in the flange 17 on the intermediate bushing 11. The short arm 21 is also adapted to abut against the rear end face of the cone clutch ring 13 as shown in solid lines in FIG. 1. The free end 25 of the lever 19 is normally biased against an eccentric cam 27 by the action of said spring 20. A dial knob 26 is provided for actuating said eccentric cam 27.

The operation of the mechanism according to the present invention is as follows: Before starting the operation of the sewing machine, the dial knob 26 is manually actuated, so that the cam 27 and the co-operating L-shape'd lever 19 are moved into the position shown in chain lines in FIG. 1, thereby releasing the operative connection between the driving pulley 5 and the intermediate bushing 11, the clutch ring 13 being slid backwardly by the action of the spring '16. The free end of the short arm 21 of the lever 19 is moved from its position shown in solid lines to the position shown in chain lines to engage with the recess 24 of the intermediate bushing 11, whereby said intermediate bushing 11 having the internal gear 12 is held against rotation. In such posit-ion, when the pulley 5 is put into operation by starting the driving motor, the sun gear 7 is rotated, so that the rotation of the sun gear 7 will be transmitted to the drum shaped extension of the bushing 3 through the planetary pinions 9 meshing with the now stationary internal gear 12 of the intermediate bushing 11, and the main shaft 2 will be rotated at reduced speed. The ratio of the speed of rotation of the sun gear 7 and the drum It) is as follows: Taking the rpm. of the sun gear 7 (pulley 5) as Ns, the rpm. of the drum 10 (the main shaft 2) as Na, number of teeth of the sun gear 7 as Zs, and the number of teeth of the internal gear 12 as Zr, the rotation of the pulley 5 will be transmitted to the drum 10 (the main shaft 2) at reduced speed according to the following:

Thus, it will be understood that, according to the pres ent invention, the starting torque of the main shaft 2 will become very large as compared with that of the main shaft directly connected to the pulley, so that the start of the sewing machine may be readily effected by means of the small capacity motor heretofore employed in the sewing machine, without causing any hinderance. When it is desired to operate the sewing machine at low speed, one may use the machine in the above mentioned condition, controlling the speed of the machine by making use of the usual controller of the driving motor. To continue the operation of the machine at high speed, the dial knob 26 is actuated to bring the cam 27 and the lever 19' to the position shown in solid lines, so that the clutch ring 13 is pushed forwardly against the action of the spring 16, and thereby the pulley 5 and the intermediate bushing 11 is operat-ively connected by means of the clutch ring. Accordingly, the direct connection of the pulley 5 with the main shaft 2 will be established by reason of the fact that the sun gear 7 and the internal gear 12 of the intermediate bushing 11 are rotated in unison.

In the speed change mechanism as described above, it will be seen that tthe planetary gear system may be put into the neutral position. According to the present invention, such a specific feature is utilized for connecting the bobbin winder assembly with the driving pulley 5, which bobbin winder assembly is constructed as shown in FIGS. 2 and 3. The reference numeral 28 designates generally a bobbin winder assembly comprising a bobbin winder pulley '29 having a friction ring and carried on a lever 30 secured to a pivot pin 31. A spring 32 has one end connected to the lever 30 and the other end secured to the sewing machine ar-m body 1, and this spring 32 has a tendency to turn the lever 30 in counterclockwise direction toward the position shown in solid lines in FIG. 2 and to turn said lever 30 in a clockwise direction toward the position shown in chain line after it is moved about half way to the chain line position, in which position the bobbin winder wheel 29 is held in frictional con tact with the driving pulley 5 as shown.

To the pivot pin 31, there is secured a stop 32' cooperating with a stud 33 for limiting the counterclockwise movement of the lever 30. The pivot pin 31 has secured thereto a short arm 34 which is connected by means of a rod 35 to a short lever 36 pivotally mounted on the shaft 18 and having an car 37, the free end of which is bent (not shown) so as to engage with the side edge of the short arm 21.

When bobbin winding, the driving pulley 5 must be held loose with respect to the main shaft 2. For this purpose, the bushing 3 fixed to the shaft 2 should be held fixed with respect to the sewing machine arm 1, and the pulley 5 and the intermediate bushing 11 be permitted free rotation, thereby shutting off the transmission of the rotation of the pulley 5 to the main shaft 2.

Now, assuming that various parts assume the solid line position in FIG. 1, in which the cone clutch ring 13 is pushed forwardly, coupling together the pulley 5 and the intermediate bushing 11, the bobbin winder assembly 28 is manually turned upwardly to bring the bobbin winder pulley 29 into frictional contact with the driving pulley 5. :By such actuation, the short lever 36 is turned in the counterclockwise direction by means of the rod 35, so that the short arm 21 of the lever 19 is acted upon by the extension or ear 37, and the free end of said short arm 21 will be disengaged from the rear end of the clutch ring 13 thus permitting the clutch ring to move to its retracted position or from the recess 24 of the intermediate bushing 11, and it comes into engagement with the recess 23 of the drum 10 which is the extension of the drum bushing 3 fixed t0 the main shaft 2, as shown in FIG. 3. Thus, the drum 10 and thus shaft 2 is held fixed relative to the sewing machine arm body 1, while the driving pulley 5 and the intermediate bushing 11 which are no longer connected by clutch ring 13 are free to rotate. In such position, by star-ting the operation of the motor, the driving pulley 5 is rotated freely without driving the main shaft 2, so that the bobbin winder wheel 29 can be driven by the pulley 5. The position of the recess 23 of the drum 10 can be set at a posit-ion such that the short arm 21 will engage with said recess 23 at the time the needle bar of the sewing machine is at the upper dead center. By this means, the sewing machine can be stopped at the upper dead center, during which the bobbin Winding operation can be effected.

If desired, in order to facilitate the engagement of the short arm 21 with the recess 23 or 24, a plurality of said recesses may be provided, or alternatively said recess may be replaced by a protrusion.

It will be seen from the foregoing description that a sewing mahine may be operated at low speed as well as at high speed by manual switching over of the speed change mechanism according to the present invention; that starting of the driving motor and low speed operation of the sewing machine may be readily effected; that the bobbin winder assembly may be connected to the a freely rotating driving pulley; and that the appearance of the sewing machine arm is not affected at all by the provision of the speed change mechanism of the present invention.

What I claim is:

-1. A speed change mechanism for a sewing machine comprising a main shaft, a support bushing fixedly mounted on said main shaft and having an outwardly extending portion wit-h a drum on the outer end thereof, a driving pulley having a flange and loosely mounted on said support bushing and having a sun gear thereon, planetary pinions carried by said outwardly extending portion and meshing with said sun gear on the driving pulley, an intermediate bushing loosely mounted on said drum and having an internal gear meshing with said planetary pinions, a clutch member axially slidably mounted and extending between said flange of the driving pulley and said intermediate bushing and engageable in clutching relationship between said flange and said intermediate bushing for connecting and disconnecting the driving pulley and the intermediate bushing, a spring normally biasing said clutch member toward its declutched position, and a manually actuatable lever having a short control arm engageable with said intermediate bushing for holding said intermediate bushing against rotation, said short control arm being movable out of engagement with said intermediate bushing and into engagement with said clutch member for holding said clutch member in operative position against the action of said spring while releasing said clutch member, whereby with the rotation of said driving pulley with said intermediate bushing held against rotation and with said clutch member declutched, the drum fixedly connected with the main shaft is rotated at reduced speed.

2. A speed change mechanism as claimed in claim 1, further comprising a cam having a dial knob engaging said lever for manipulating said lever having the short arm thereon.

3. A speed change mechanism as claimed in claim '1, including a bobbin Winder assembly having a bobbin Winder pulley adapted to be brought into frictional engage-merit with said driving pulley and means operatively connecting said Winder assembly With said short control arm whereby u-pon movement of said bobbin Winder assembly into engagement with said driving pulley said short control arm is moved into engagement with said drum 6 for fixedly holding said drum and said main shaft and said driving pulley is freed to operate said winder asse-nrbly.

References Cited UNITED STATES PATENTS 2,882,757 4/1959 Edsall 74--785 XR 2,966,810 1/1961 Hayes. 3,095,765 7/1963 Perla 112--22O XR 10 JORDAN FRANKLIN, Primary Examiner.

H. H. HUNTER, Examiner. 

